Facile Preparation of NiO/Ni Nanocomposite and its Electrochemical Capacitive Behaviors

2011 ◽  
Vol 306-307 ◽  
pp. 134-138 ◽  
Author(s):  
Wei Dong Yin ◽  
Gui Lian Li ◽  
Xian Ming Liu
Keyword(s):  
Specific Capacitance ◽  
Oxidation Process ◽  
Aqueous Electrolyte ◽  
High Specific Capacitance ◽  
Cycling Performance ◽  
Charge Transfer Resistance ◽  
Electrochemical Performances ◽  
Composite Electrodes ◽  
Galvanostatic Charge ◽  
Transfer Resistance

NiO/Ni nanocomposites were prepared by chemically reduction-oxidation process in tetra-ethylene glycol (TEG) solution. The structure and morphology of the samples were examined by XRD and SEM. The results indicated the composite consisted of NiO and Ni and exhibited spherical morphology with diameter of 50-200 nm. The electrochemical performances of composite electrodes used in electrochemical capacitors were studied. The electrochemical measurements were carried out using cyclic voltammetry, galvanostatic charge/discharge and impedance spectroscopy in 6M KOH aqueous electrolyte using three-electrode Swagelok systems. The results showed that the composite had a high specific capacitance and excellent capacitive behavior. The specific capacitance of the composite decreased to 192F/g after 500 cycles. Due to the existance of Ni, the charge transfer resistance is lower than 1Ω. It revealed that the composite exhibited good cycling performance.

Facile synthesis of γ-MnO2/rice husk-based-activated carbon and its electrochemical properties

2017 ◽  
Vol 10 (05) ◽  
pp. 1750057 ◽  
Author(s):  
Xiaolan Song ◽  
Hailong Duan ◽  
Ying Zhang ◽  
Haibo Wang ◽  
Hongyun Cao
Keyword(s):  
Activated Carbon ◽  
Specific Capacitance ◽  
Low Cost ◽  
Chemical Deposition ◽  
Electrochemical Capacitor ◽  
High Specific Capacitance ◽  
Charge Transfer Resistance ◽  
Electrochemical Performances ◽  
Equivalent Series Resistance ◽  
Transfer Resistance

In this study, composite [Formula: see text]-MnO2/activated carbon (AC) was prepared by chemical deposition method, and then it was assembled into electrode and electrochemical capacitor. Effects of reaction temperature and MnO2 content were studied. Materials were characterized by X-ray diffraction, scanning electron microscope and electrochemical test. MnO2 prepared at 30[Formula: see text]C was amorphous, and it displayed the high specific capacitance as nearly four times as MnO2 at 80[Formula: see text]C. Due to MnO2 particles which would block carbon pores when its content was too high, the composite containing 30% of MnO2 exhibited the largest specific capacitance of 278.3[Formula: see text]F/g at 0.2[Formula: see text]A/g in K2SO4 electrolyte. The equivalent series resistance and charge transfer resistance of material were only 1.35[Formula: see text][Formula: see text] and 1.41[Formula: see text][Formula: see text], respectively. After 1000 cycles, the capacitance retention was still 91.6%. It indicated that chemical deposition was a facile, low cost and effective method to prepare MnO2/AC with good electrochemical performances.

Facile Synthesis of Polypyrrole Nanofibers/Co-MOF Composite and Its Lithium Storage Properties

2020 ◽  
Vol 12 (4) ◽  
pp. 486-491
Author(s):  
Jinlei Wang ◽  
Na Cao ◽  
Huiling Du ◽  
Xian Du ◽  
Hai Lu ◽  
...  
Keyword(s):  
Electrode Materials ◽  
Rate Capability ◽  
Lithium Ion ◽  
Reversible Capacity ◽  
Cycling Performance ◽  
Charge Transfer Resistance ◽  
Growth Strategy ◽  
Composite Electrodes ◽  
Lithium Storage ◽  
Transfer Resistance

Metal-organic frameworks (MOFs) have recently emerged as promising electrode materials for lithium-ion batteries (LIBs). However, poor electrical conductivity in most MOFs limits their electrochemical performance. In this work, the integration of flaky cobalt 1,4-benzenedicarboxylate (Co-BDC) MOF with conductive polypyrrole (PPy) nanofibers via in-situ growth strategy was explored for developing novel anode materials for LIBs. Electrochemical studies showed that PPy/Co-BDC composites exhibited enhanced cycling performance (a reversible capacity of ca. 364 mA h g–1 at a current density of 50 mA g–1 after 100 cycles) and rate capability, com- pared with the pristine Co-BDC. The well dispersion of Co-BDC on polypyrrole nanofibers and the decrease in charge-transfer resistance of the composite electrodes accounted for the improvement of electrochemical properties.

scholarly journals Carbon Nanotube Fibers Decorated with MnO2 for Wire-Shaped Supercapacitor

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3479
Author(s):  
Luman Zhang ◽  
Xuan Zhang ◽  
Jian Wang ◽  
David Seveno ◽  
Jan Fransaer ◽  
...  
Keyword(s):  
Specific Capacitance ◽  
Lithium Ion ◽  
High Strength ◽  
High Specific Capacitance ◽  
Cycling Performance ◽  
Electrochemical Performances ◽  
Wearable Electronics ◽  
Energy Storage Devices ◽  
Energy Applications ◽  
High Flexibility

Fibers made from CNTs (CNT fibers) have the potential to form high-strength, lightweight materials with superior electrical conductivity. CNT fibers have attracted great attention in relation to various applications, in particular as conductive electrodes in energy applications, such as capacitors, lithium-ion batteries, and solar cells. Among these, wire-shaped supercapacitors demonstrate various advantages for use in lightweight and wearable electronics. However, making electrodes with uniform structures and desirable electrochemical performances still remains a challenge. In this study, dry-spun CNT fibers from CNT carpets were homogeneously loaded with MnO2 nanoflakes through the treatment of KMnO4. These functionalized fibers were systematically characterized in terms of their morphology, surface and mechanical properties, and electrochemical performance. The resulting MnO2–CNT fiber electrode showed high specific capacitance (231.3 F/g) in a Na2SO4 electrolyte, 23 times higher than the specific capacitance of the bare CNT fibers. The symmetric wire-shaped supercapacitor composed of CNT–MnO2 fiber electrodes and a PVA/H3PO4 electrolyte possesses an energy density of 86 nWh/cm and good cycling performance. Combined with its light weight and high flexibility, this CNT-based wire-shaped supercapacitor shows promise for applications in flexible and wearable energy storage devices.

Preparation and electrochemical characterization of PANI/MnCo2O4 nanocomposite as supercapacitor electrode material

2018 ◽  
Vol 96 (5) ◽  
pp. 477-483 ◽  
Author(s):  
Saeid Panahi ◽  
Moosa Es’haghi
Keyword(s):  
Specific Capacitance ◽  
Surface Characterization ◽  
Electrochemical Impedance ◽  
Rate Capability ◽  
Cycling Performance ◽  
Charge Transfer Resistance ◽  
X Ray Diffraction ◽  
Supercapacitor Electrode ◽  
Transfer Resistance

In this work, PANI/MnCo2O4 nanocomposite was prepared via in-situ chemical polymerization method. Materials synthesized were characterized by FTIR spectroscopy, X-ray diffraction, and scanning electron spectroscopy. In addition, surface characterization of samples such as specific surface area, pore volume, and pore size distribution was studied. Supercapacitor capability of materials was investigated in 1 mol L–1 Na2SO4 solution using cyclic voltammetry in different potential scan rates and electrochemical impedance spectroscopy (EIS). The specific capacitance of materials was calculated, and it was observed that the specific capacitance of PANI/MnCo2O4 nanocomposite was 185 F g−1, much larger than PANI. Moreover, the prepared nanocomposite exhibited better rate capability in scan rate of 100 mV s−1 with respect to PANI. The EIS experiments revealed that the nanocomposite has lower charge transfer resistance compared with pure PANI. Subsequently, it was shown that the nanocomposite cycling performance was superior to the PANI cycling performance.

Electrochemical Properties of Electrodeposited MnO2 Nanoparticles

2015 ◽  
Vol 1113 ◽  
pp. 550-553 ◽  
Author(s):  
Gomaa Abdelgawad Mohammed Ali ◽  
Mashitah M. Yusoff ◽  
Kwok Feng Chong
Keyword(s):  
Electrochemical Properties ◽  
High Specific Capacitance ◽  
Xrd Analysis ◽  
Charge Transfer Resistance ◽  
Electrochemical Studies ◽  
Galvanostatic Charge ◽  
Transfer Resistance ◽  
Electrodeposited Film ◽  
Solution Resistance ◽  
Charge Discharge

The present study shows the electrodeposition of MnO2 from KMnO2 solution and its electrochemical studies. XRD analysis shows the electrodeposited MnO2 has nano-sized particle of 18 nm. The electrochemical properties have been investigated using the cyclic voltammetry, galvanostatic charge/discharge and impedance techniques. The electrodeposited MnO2 shows good electrochemical behavior with high specific capacitance value of ca. 306 F g-1. Moreover, it shows high capacitance stability of 90% over 1000 charge/discharge cycles. Impedance result shows low solution resistance and charge transfer resistance, an indication of the conductive nature for the electrodeposited film.

Electrochemical Characterization of Graphene–LiMn2O4 Composite Cathode Material for Aqueous Rechargeable Lithium Batteries

2021 ◽  
Vol 23 (09) ◽  
pp. 967-980
Author(s):  
K.C. Mahesh ◽  
◽  
G.S. Suresh ◽  
Keyword(s):  
Cathode Material ◽  
Charge Transfer Resistance ◽  
Active Surface Area ◽  
Electrochemical Performances ◽  
Composite Electrodes ◽  
Rechargeable Lithium Batteries ◽  
Lithium Storage ◽  
Transfer Resistance ◽  
Graphene Layers ◽  
Active Nanoparticles

A series of graphene– LiMn2O4 composite electrodes were prepared by physical mixing of graphene powder and LiMn2O4 cathode material. LiMn2O4was synthesized by reactions under autogenic pressure at elevated temperature method. CV, galvanostatic charge-discharge experiments and EIS studies revealed that the addition of graphene significantly decreases the charge-transfer resistance of LiMn2O4 electrodes. 5 wt. % graphene–LiMn2O4 composite electrode exhibits better electrochemical performance by increasing the reaction reversibility and capacity compared to that of the pristine LiMn2O4 electrode. Improved electrochemical performances are thus achieved, owing to the synergic effect between graphene and the LiMn2O4 active nanoparticles. The ultrathin flexible graphene layers can provide a support for anchoring well-dispersed active cathode particles and work as a highly conductive matrix for enabling good contact between them. At the same time, the anchoring of active nanoparticles on graphene effectively reduces the degree of restacking of graphene sheets and consequently keeps a highly active surface area which increases the lithium storage capacity and cycling performance.

Electrochemical Performances of Yttrium Doped Li3V2–XYX(PO4)3/C Cathode Material for Lithium Secondary Battery

2015 ◽  
Vol 15 (10) ◽  
pp. 8042-8047 ◽  
Author(s):  
Minchan Jeong ◽  
Hyun-Soo Kim ◽  
Dong-Sik Bae ◽  
Chang-Woo Lee ◽  
Bong-Soo Jin
Keyword(s):  
Electrochemical Impedance ◽  
Rate Capability ◽  
Cycling Performance ◽  
Charge Transfer Resistance ◽  
Electrochemical Performances ◽  
X Ray Diffraction ◽  
Lithium Secondary Battery ◽  
Capacity Retention ◽  
Solid State Method ◽  
Transfer Resistance

In this study, the Li3V2–X YX(PO4)3 compounds have been synthesized by a simple solid state method. In addition, a polyurethane was added to apply carbon coating on the surface of the Li3V2–X YX(PO4)3 particles for enhancement of the electrical conductivity. The crystal structure and morphology of the synthesized Li3V2–XYX(PO4)3/C (LVYP/C) was investigated using an X-ray diffraction (XRD) and a scanning electron microscopy (SEM) systematically. The electrochemical performance of synthesized material, such as the initial capacity, rate capability, cycling performance and EIS was evaluated. The sizes of synthesized particle ranged from 1 to 5 μm. The Li3V2–XYX(PO4)3/C (X = 0.02) delivered the initial discharge capacity of 171.5 mAh · g–1 at 0.1C rate. It showed a capacity retention ratio of 73.0% at 1.0C after 100th cycle. The electrochemical impedance spectroscopies (EIS) results revealed that the charge transfer resistance of the material decreases by Y doping.

scholarly journals Electrochemically Reduced Titania Nanotube Synthesized from Glycerol-Based Electrolyte as Supercapacitor Electrode

Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2767 ◽  
Author(s):  
Muhammad Muhammad Muzakir ◽  
Zulkarnain Zainal ◽  
Hong Ngee Lim ◽  
Abdul Halim Abdullah ◽  
Noor Nazihah Bahrudin ◽  
...  
Keyword(s):  
Specific Capacitance ◽  
Reduction Process ◽  
High Specific Capacitance ◽  
Charge Transfer Resistance ◽  
Tube Diameter ◽  
Titania Nanotubes ◽  
Supercapacitor Electrode ◽  
Transfer Resistance ◽  
Self Organized ◽  
Electrons And Ions

In this paper the synthesis of self-organized Titania nanotubes (TNTs) by a facile potentiostatic anodization in a glycerol-based electrolyte is reported. The optimized TNTs were subsequently reduced through a cathodic reduction process to enhance its capacitive performance. FESEM and XRD were used to characterize the morphology and crystal structure of the synthesized samples. XPS analysis confirmed the reduction of Ti4+ to Ti3+ ions in the reduced Titania nanotubes (R-TNTs). The tube diameter and separation between the tubes were greatly influenced by the applied voltage. TNTs synthesized at voltage of 30 V for 60 min exhibited 86 nm and 1.1 µm of tube diameter and length, respectively and showed high specific capacitance of 0.33 mF cm−2 at current density of 0.02 mA cm−2. After reduction at 5 V for 30 s, the specific capacitance increased by about seven times (2.28 mF cm−2) at 0.5 mA cm−2 and recorded about 86% capacitance retention after 1000 continuous cycling at 0.2 mA cm−2, as compared to TNTs, retained about 61% at 0.01 mA cm−2. The charge transfer resistance drastically reduced from 6.2 Ω for TNTs to 0.55 Ω for R-TNTs, indicating an improvement in the transfer of electrons and ions across the electrode–electrolyte interface.

scholarly journals Synthesis and Characterization of Electrodeposited C-PANI-Pd-Ni Composite Electrocatalyst for Methanol Oxidation

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
S. S. Mahapatra ◽  
S. Shekhar ◽  
B. K. Thakur ◽  
H. Priyadarshi
Keyword(s):  
Methanol Oxidation ◽  
Electrocatalytic Activity ◽  
Electrochemical Impedance ◽  
Synergistic Effects ◽  
Catalytic Performance ◽  
Charge Transfer Resistance ◽  
Pani Film ◽  
Composite Electrodes ◽  
Transfer Resistance ◽  
Onset Potential

Electropolymerization of aniline at the graphite electrodes was achieved by potentiodynamic method. Electrodeposition of Pd (C-PANI-Pd) and Ni (C-PANI-Ni) and codeposition of Pd-Ni (C-PANI-Pd-Ni) microparticles into the polyaniline (PANI) film coated graphite (C-PANI) were carried out under galvanostatic control. The morphology and composition of the composite electrodes were obtained using scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX) techniques. The electrochemical behavior and electrocatalytic activity of the electrode were characterized using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and chronoamperometric (CA) methods in acidic medium. The C-PANI-Pd-Ni electrode showed an improved catalytic performance towards methanol oxidation in terms of lower onset potential, higher anodic oxidation current, greater stability, lower activation energy, and lower charge transfer resistance. The enhanced electrocatalytic activity might be due to the greater permeability of C-PANI films for methanol molecules, better dispersion of Pd-Ni microparticles into the polymer matrixes, and the synergistic effects between the dispersed metal particles and their matrixes.

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